221 research outputs found

    Square root-based multi-source early PSD estimation and recursive RETF update in reverberant environments by means of the orthogonal Procrustes problem

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    Multi-channel short-time Fourier transform (STFT) domain-based processing of reverberant microphone signals commonly relies on power-spectral-density (PSD) estimates of early source images, where early refers to reflections contained within the same STFT frame. State-of-the-art approaches to multi-source early PSD estimation, given an estimate of the associated relative early transfer functions (RETFs), conventionally minimize the approximation error defined with respect to the early correlation matrix, requiring non-negative inequality constraints on the PSDs. Instead, we here propose to factorize the early correlation matrix and minimize the approximation error defined with respect to the early-correlation-matrix square root. The proposed minimization problem -- constituting a generalization of the so-called orthogonal Procrustes problem -- seeks a unitary matrix and the square roots of the early PSDs up to an arbitrary complex argument, making non-negative inequality constraints redundant. A solution is obtained iteratively, requiring one singular value decomposition (SVD) per iteration. The estimated unitary matrix and early PSD square roots further allow to recursively update the RETF estimate, which is not inherently possible in the conventional approach. An estimate of the said early-correlation-matrix square root itself is obtained by means of the generalized eigenvalue decomposition (GEVD), where we further propose to restore non-stationarities by desmoothing the generalized eigenvalues in order to compensate for inevitable recursive averaging. Simulation results indicate fast convergence of the proposed multi-source early PSD estimation approach in only one iteration if initialized appropriately, and better performance as compared to the conventional approach

    Localization of a Virtual Wall by Means of Active Echolocation by Untrained Sighted Persons

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    The active sensing and perception of the environment by auditory means is typically known as echolocation and it can be acquired by humans, who can profit from it in the absence of vision. We investigated the ability of twentyone untrained sighted participants to use echolocation with self-generated oral clicks for aligning themselves within the horizontal plane towards a virtual wall, emulated with an acoustic virtual reality system, at distances between 1 and 32 m, in the absence of background noise and reverberation. Participants were able to detect the virtual wall on 61% of the trials, although with large di↵erences across individuals and distances. The use of louder and shorter clicks led to an increased performance, whereas the use of clicks with lower frequency content allowed for the use of interaural time di↵erences to improve the accuracy of reflection localization at very long distances. The distance of 2 m was the most difficult to detect and localize, whereas the furthest distances of 16 and 32 m were the easiest ones. Thus, echolocation may be used e↵ectively to identify large distant environmental landmarks such as buildings

    Phenotypes induced by NM causing α-skeletal muscle actin mutants in fibroblasts, Sol 8 myoblasts and myotubes

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    <p>Abstract</p> <p>Background</p> <p>Nemaline myopathy is a neuromuscular disorder characterized by the presence of nemaline bodies in patient muscles. 20% of the cases are associated with α-skeletal muscle actin mutations. We previously showed that actin mutations can cause four different biochemical phenotypes and that expression of NM associated actin mutants in fibroblasts, myoblasts and myotubes induces a range of cellular defects.</p> <p>Findings</p> <p>We conducted the same biochemical experiments for twelve new actin mutants associated with nemaline myopathy. We observed folding and polymerization defects. Immunostainings of these and eight other mutants in transfected cells revealed typical cellular defects such as nemaline rods or aggregates, decreased incorporation in F-actin structures, membrane blebbing, the formation of thickened actin fibres and cell membrane blebbing in myotubes.</p> <p>Conclusion</p> <p>Our results confirm that NM associated α-actin mutations induce a range of defects at the biochemical level as well as in cultured fibroblasts and muscle cells.</p

    Dosage of pain rehabilitation programmes for patients with chronic musculoskeletal pain:a non-inferiority randomised controlled trial

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    PURPOSE: To analyse the effects of interdisciplinary pain rehabilitation programmes with different dosages; care as usual versus short form. METHODS: A single blinded, two armed, randomised controlled trial, with non-inferiority design was performed. All patients with chronic musculoskeletal pain referred to an outpatient multidisciplinary pain rehabilitation programme were eligible for this study. Only dosage differed, content was similar. The difference on Pain Disability Index was the primary outcome measure. Four points difference on Pain Disability Index was applied as a non-inferiority margin. Treatment effects within groups were expressed in standardised mean difference and effect sizes were calculated between the groups. RESULTS: Because care as usual was frequently extended, the difference in dosage between groups was limited. The study was stopped prematurely because of an a-priori stopping rule. Interim analyses are presented. Both groups (care as usual n = 58, short form n = 54) improved significantly (mean Pain Disability Index change care as usual: -10.8; short form: -8.3). Mean difference between groups was 2.5 points (95% confidence interval was -2.2 to 7.3). Effect size between groups was 0.2. CONCLUSIONS: The 95% confidence interval for the difference in mean pain disability reduction exceeded the upper limit of the non-inferiority margin. The results of the primary analyses of this trial are, therefore, inconclusive. Ancillary analyses revealed that programme dosage was not associated with differences in the disability outcomes. Implications for rehabilitation Optimum dosage of interdisciplinary pain rehabilitation programs is unknown and scarcely studied. This study is the first to analyse dosage as primary aim. Although results are inconclusive, they also suggest that differences in dosage may not automatically lead to differences in effects. Further research is needed to analyse what dosage works for whom; to detect optimum effective and cost-effective dosage of pain rehabilitation programmes

    Including personal boundaries scale: development and psychometric properties of a measurement for nurses' self-efficacy toward intimate and sexual behavior in dementia care

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    BackgroundPerson-centered nursing home care recognizes the intimate and sexual needs of residents with dementia but lacks guidance for nurses to address them while effectively respecting their personal boundaries. The Including Personal Boundaries (IPB) scale was developed to complement clinical and scientific efforts to support both nurse and resident wellbeing.MethodsThrough a co-creative process, theoretical principles, day-to-day experiences, and expert knowledge were integrated into an initial nineteen-item version of the IPB scale. The pilot sample comprised 297 Dutch (vocational) nurses in dementia nursing care.ResultsAfter Principal Component Analysis, nine items with strong factor loadings (&gt;0.6) were retained. Internal reliability measures supported the item selection, such as high internal consistency (α = 0.866) and adequate corrected item-total correlations (0.532–0.781).ConclusionThe presented IPB scale, a nine-item scale, is a short, robust measure to assess nurses' self-efficacy in their capabilities to include personal boundaries (physical and emotional) when confronted with the intimate and sexual behaviors of residents with dementia. Further validation is recommended. The IPB scale could provide valuable insights for research, clinical practice, and education

    Sales promotions and channel coordination

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    Consumer sales promotions are usually the result of the decisions of two marketing channel parties, the manufacturer and the retailer. In making these decisions, each party normally follows its own interest: i.e. maximizes its own profit. Unfortunately, this results in a suboptimal outcome for the channel as a whole. Independent profit maximization by channel parties leads to a lack of channel coordination with the implication of leaving money on the table. This may well contribute to the notoriously low profitability of sales promotions. This paper first shows analytically why the suboptimality occurs, and then presents an empirical demonstration, using a unique dataset from an Efficient Consumer Response (ECR) project; ECR is a movement in which parties work together to optimize the distribution channel). In this dataset, actual profit is only a small fraction of potential profit, implying that there is a large degree of suboptimality. It is important that (1) channel parties are aware of this suboptimality; and (2) that they have tools to deal with it. Solutions to the channel coordination problem should ensure that the goals of the individual channel parties are aligned with the goals of the channel as a whole. The paper proposes one particular agreement for this purpose, called proportional discount sharing. Application to the ECR data shows a win-win result for both the manufacturer and the retailer. Recognition of the channel coordination problem by the manufacturer and the retailer is the necessary starting point for agreeing on a way of solving it in a win-win fashion

    Marketing (as) Rhetoric: paradigms, provocations, and perspectives

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    In this collection of short, invited essays on the topic of marketing (as) rhetoric we deal with a variety of issues that demonstrate the centrality of rhetoric and rhetorical considerations to the pursuit of marketing scholarship, research and practice. Stephen Brown examines the enduring rhetorical power of the 4Ps; Chris Hackley argues for the critical power of rhetorical orientations in marketing scholarship but cautions us on the need to work harder in conceptually connecting rhetorical theory and modern marketing frameworks; Shelby Hunt explains how rhetorical processes are incorporated in his inductive realist model of theory generation, using one of his most successful publications as an illustration; Charles Marsh demonstrates what Isocrates’ broad rhetorical project has to teach us about the importance of reputation cultivation in modern marketing; Nicholas O’Shaughnessy uses an analysis of Trump’s discourse to argue that political marketing as it is currently conceived is ill-equipped to engage effectively with the rhetorical force of Trump’s ‘unmarketing’; Barbara Phillips uses Vygotsky’s work on imagination to investigate the important of pleasure and play in advertising rhetoric; and finally, David Tonks, who in many ways started it all, reiterates the need for marketers to recognise the strength of the relationship between marketing and persuasion

    A global experiment on motivating social distancing during the COVID-19 pandemic

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    Finding communication strategies that effectively motivate social distancing continues to be a global public health priority during the COVID-19 pandemic. This cross-country, preregistered experiment (n = 25,718 from 89 countries) tested hypotheses concerning generalizable positive and negative outcomes of social distancing messages that promoted personal agency and reflective choices (i.e., an autonomy-supportive message) or were restrictive and shaming (i.e., a controlling message) compared with no message at all. Results partially supported experimental hypotheses in that the controlling message increased controlled motivation (a poorly internalized form of motivation relying on shame, guilt, and fear of social consequences) relative to no message. On the other hand, the autonomy-supportive message lowered feelings of defiance compared with the controlling message, but the controlling message did not differ from receiving no message at all. Unexpectedly, messages did not influence autonomous motivation (a highly internalized form of motivation relying on one’s core values) or behavioral intentions. Results supported hypothesized associations between people’s existing autonomous and controlled motivations and self-reported behavioral intentions to engage in social distancing. Controlled motivation was associated with more defiance and less long-term behavioral intention to engage in social distancing, whereas autonomous motivation was associated with less defiance and more short- and long-term intentions to social distance. Overall, this work highlights the potential harm of using shaming and pressuring language in public health communication, with implications for the current and future global health challenges
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